Evaluation of value-added by-products from steam explosion lignocellulosic biomass (Triticum aestivum, Zea mays, and Phragmites australis)

Significant biorefinery potential is held in by-products generated during the production of bio-based insulation material through steam explosion pretreatment of lignocellulosic materials. However, the composition and potential uses of these by-products have not been fully explored. The objective of this study is to characterize the major decomposition components generated during steam explosion pretreatment of wheat (Triticum aestivum) straw, corn (Zea mays) stalks, and reed (Phragmites australis) as second-generation lignocellulosic biomass, in the separated liquid fraction consisting of volatiles and water-dissolved compounds. Decomposition occurred via steam explosion characterized by two key parameters: (1) severity factor (logR0), which combines reaction time and temperature, ranging from 3.25 to 3.75, and (2) pressure, set at 16 and 30 bar. Ultra-high-performance liquid chromatography and gas chromatography were used to analyze sugars, as well as phenolics, furan derivatives, and acids. The highest simple sugar yield (59.2 g/kg biomass) was detected in reed liquid fraction, significantly exceeding corn stalks and wheat straw (21.3 g/kg biomass each). Subsequent acid hydrolysis enhanced the simple sugar content of reed liquid fraction up to 150.4 g/kg biomass, up to 64.5 g/kg biomass for corn stalks and up to 88.3 g/kg biomass wheat straw. These findings show the promising potential of bio-based insulation by-products generated by steam explosion. The sugar-rich liquid fraction can be beneficial for circular bio-based economy especially in the biofuel or biopolymer industry, particularly from reed, enhancing the overall utilization of lignocellulosic materials in a biorefinery context.